Functionalized titanate nanotubes for efficient lithium adsorption and recovery from aqueous media

In this study, the potential for adsorption of lithium ions (Li⁺) by pristine titanate nanotubes (pTNTs) and organic compound (OC)-functionalized TNTs was examined. We used a simple hydrothermal method for fabricating the pTNTs at 130 ​°C, and these synthesized p-TNTs were functionalized with different OCs, including urea, melamine, and polyacrylonitrile, using titanium (IV) oxide powder as a precursor via a wet impregnation approach. The crystallinity, morphology, and functional group properties of the prepared adsorbents were characterized. The Li⁺ adsorption mechanism is considered to be an ion exchange reaction with Li⁺ ions in solution, and H⁺ ions exist in the interlayers of the pristine and functionalized TNTs. Different kinetic models were applied to equilibrium experimental data to determine the rate and nature of the adsorption process. The recovery of Li⁺ ions was achieved by using hydrochloric acid as an extracting agent in three repeated cycles. The presented study showed that the prepared adsorbents have good potential to adsorb and desorb Li⁺ ions from aqueous solutions and can be used for future studies.